This application proposes a new set of related data collections designed to better understand the full range of intellectual development across the full life-span. Rather than concentrate on the typical measures of broad intellectual abilities common in cognitive aging research, this project concerns what are termed "knowledge structures," or "what adults know, even though such knowledge may not be universal." A five-year research plan is proposed including a broad array of measures administered mainly via a computer on 550 participants in the first year, 650 in the second year, with follow-ups at one-to- two years later. This work is based on a series of prior researches and a "new" theory developed by the principal investigator. One key goal will be to provide a "better metric to understanding the intellectual capabilities and limitations of adults at various chronological ages."